With the natural number entered here, it will build a table with all of the possibles combinations of nucleotids with that lenght, and calculate its frequency in the DNA chain.
For example, if the entered length is 2, the possibles tuples are:
AA |
AC |
AG |
AT |
CA |
CC |
CG |
CT |
GA |
GC |
GG |
GT |
TA |
TC |
TG |
TT |